If you hose out the cavity of a deer please make sure to wipe it dry afterwards. The moisture can create an environment that is ideal for bacterial growth.
Also, I would not use 50 degrees as an ok temperature. Please stick with my suggested 40 degrees. As anything above 40 is again an ideal environment for bacterial growth. The following link is from the USDA and discusses the food temperature danger zone (40 degrees to 140): How Temperatures Affect Food
BTW, a butcher will not be able to tell if meat is bad unless it smells rancid, or unless they have a microscope and testing equipment to see the bacteria. Unfortunately, bacteria can make you sick without smelling bad, as after it is ingested it can continue to grow and multiply and infect your body.
I am glad that we agree that a gut shot will not ruin the meat.